As Maxium4x4 said it was a limited run of bad radiators.

"Radiator coolant leak:
Some radiators have developed leaks at the end tanks due to poor tank crimping. Radiators with a build date of 8-6-07 and later have been inspected and certified. Radiators that were built prior to that should be inspected for incomplete crimping of the end tabs at the tanks, as well as cracks in the tank around the transmission cooler line fittings. Build date information is on a yellow or white sticker on the top radiator cross rail. Replacement radiators should be inspected for damage prior to installation. Broadcast Message 0246, 0107."